/*#father{
width: 300px;
height: 300px;
background: #ccc;
display: table-cell;
vertical-align: middle;
text-align: center;
}
#child{
display: inline-block;
width: 50px;
height: 50px;
background: red;
}*/
/*#father{
width: 300px;
height: 300px;
background: #ccc;
display: flex;
justify-content: center;
align-items: center;
-webkit-align-content: center;
-webkit-align-items: center;
}
#child{
width: 50px;
height: 50px;
background: red;
}*/
/*#father{
position: relative;
width: 300px;
height: 300px;
background: #ccc;
}*/
/*#child{
position: absolute;
width: 50px;
height: 50px;
background: red;
left: 50%;
top: 50%;
-webkit-transform: translateY(-50%) translateX(-50%);
-moz-transform: translateY(-50%) translateX(-50%);
-o-transform: translateY(-50%) translateX(-50%);
-ms-transform: translateY(-50%) translateX(-50%);
}*/
/*#father{
position: relative;
width: 300px;
height: 300px;
background: #ccc;
}
#child{
position: absolute;
width: 50px;
height: 50px;
background: red;
left: 50%;
top: 50%;
margin-left: -25px;
margin-top: -25px;
}*/
/*#father{
position: relative;
width: 300px;
height: 300px;
background: #ccc;
}
#child{
position: absolute;
width: 50px;
height: 50px;
background: red;
left: 0;
top: 0;
right: 0;
bottom: 0;
margin: auto;
}*/
//利用盒模型
.father{
width: 100%;
height: 200px;
background: red;
display: flex;
flex-direction: row;
justify-content: space-between;
}
space-between設置的是子控件左中右分佈，center可以設置子空間居中顯示
以上是標籤居中的幾種常用方式，還會完善。